European patent 1894469 describes an animal trap which has a generally cylindrical housing which is arranged to be deployed in a substantially vertical position. Movable within the cylindrical housing is a closing part which is held against spring pressure in an upper position. When an animal pushes against a pivotable trigger mechanism extending in an opening at the base of the trap, the trap is triggered and the closing part is propelled downwardly where it can exert a lethal closing force on an animal in the opening.
This known trap has a number of disadvantages. First of all, the trigger mechanism hangs on surfaces of the closing part and there can be difficulties in setting the trap unless it is arranged accurately vertical so that the trigger mechanism hangs, under gravity, in the vertical position. Furthermore, this known trap has to be fixed so that it extends into a tunnel, which restricts its usefulness. The trap is also made of a number of interengaging separate pieces. This means that it is expensive to manufacture and to assemble and is not always reliable in operation.